how does windows know that usb mouse is plugged-in?

[abdalla]

HI,

how does windows know that usb mouse is plugged-in?

although i didn`t install any Driver??



thx

 

[ahmed osama]

Re: how windows knows that mouse usb is plugged ?

HI,


how windows knows that USB mouse is plugged in ?

although i didn`t install any Driver??



thx

Sure It asking Google

 

[A.Anand Srinivasan]

how windows knows that mouse usb is plugged ?

once we plug it in it gets supply from the port and it notifies it has been plugged in by setting a particular data line high or low...

 

[laktronics]

Re: how windows knows that mouse usb is plugged ?

Hi,
Yes, to be more specific, when no device is plugged into a USB port, the D+ and D- lines of the USB port will be in low state. If the device pluggedin is a full speed USB device(12Mbps), a resistor connected to Vcc line of the port inside the device will pull up the D+ line and in case of a slow speed USB device (1.5Mbps), the D- line will be pulled up. This change of DC voltage of the data line will be detected by the USB hub.
The PC software regularly keeps polling each connected hub to find out if any new device is connected to it and the hub in turn replies back when a device connection is detected. Then the PC software initiates its enumeration checks and finds out the hardware details of the connected device. It in turn looks for matching device driver software that best suits the connected hardware and allocates to it. If no suitable software is found, it flashes on screen a message as an 'unknown device found'.
Regards,
Laktronics

 

[abdalla]

Re: how windows knows that mouse usb is plugged ?

Hi,
Yes, to be more specific, when no device is plugged into a USB port, the D+ and D- lines of the USB port will be in low state. If the device pluggedin is a full speed USB device(12Mbps), a resistor connected to Vcc line of the port inside the device will pull up the D+ line and in case of a slow speed USB device (1.5Mbps), the D- line will be pulled up. This change of DC voltage of the data line will be detected by the USB hub.
The PC software regularly keeps polling each connected hub to find out if any new device is connected to it and the hub in turn replies back when a device connection is detected. Then the PC software initiates its enumeration checks and finds out the hardware details of the connected device. It in turn looks for matching device driver software that best suits the connected hardware and allocates to it. If no suitable software is found, it flashes on screen a message as an 'unknown device found'.
Regards,
Laktronics

thx so much is there something called HID mouse protocol??

thx

 

[House_Cat]

Re: how windows knows that mouse usb is plugged ?

thx so much is there something called HID mouse protocol??
thx

Yes - HID stands for "Human Interface Device". The protocol defines what kind of device is connected to the port.

See the USB reference document at: https://www.usb.org/developers/devclass_docs/HID1_11.pdf